Jiacun Fm

Himalayas. The type section is in roadcuts along the Jiacun-Yali and Lhasa-Zham highways in Nyalam (28°26'N, 85°54'E). The Jiacun Fm is derived from Jiacun Gr proposed by Wang Yigang in 1974. The Jiacun Gr was divided into upper and lower formations (Wang, 1974). Lin Baoyu et al. (1982) and Chen Ting'en (1984) redefined the Wang's lower formation as the Jiacun Fm, and his upper formation, the Jiaqu Fm (Lin et al., 1982) or the Quanshang Fm and Alai Fm (Chen, 1984). According to the nomenclature of lithostratigraphic unit, the consideration following the definition of the Lin's Jiacun Fm in the present book is not reasonable. This consideration is maintained here because there is not a suitable name replacing the previous lower formation of the Jiacun Gr, i.e. the present Jiacun Fm.

Synonym: (甲村组）

It is dominated by gray and dark gray limestone intercalated with dolomitic limestone, calcareous siltstone and fine-grained sandstone. In the type area, the Jiacun Fm is 720 m thick.

This stratigraphic unit yields conodont of Juanognathus variabilis zone, Amorphognathus variabilis zone, cephalopods of Ordosoceras-Manchuroceras zone and Dideroceras- Paradnatoceras assemblage, in ascending order, and also the Aporthophyla fauna.